scholarly journals Effect of substituent pattern and molecular weight of cellulose ethers on interactions with different bile salts

2015 ◽  
Vol 6 (3) ◽  
pp. 730-739 ◽  
Author(s):  
Amelia Torcello-Gómez ◽  
Cristina Fernández Fraguas ◽  
Mike J. Ridout ◽  
Nicola C. Woodward ◽  
Peter J. Wilde ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Aqueous Phase ◽  
Bile Salts ◽  
Cellulose Ethers ◽  
Type Pattern

Cellulose ethers interact with bile salts in the aqueous phase. These interactions are affected by the substituent type/pattern of cellulose ethers rather than their molecular weight and by the hydrophobicity of bile salts.

Interactions between Pluronics (F127 and F68) and Bile Salts (NaTDC) in the Aqueous Phase and the Interface of Oil-in-Water Emulsions

Langmuir ◽  
2013 ◽  
Vol 29 (8) ◽  
pp. 2520-2529 ◽  
Author(s):  
Amelia Torcello-Gómez ◽  
Julia Maldonado-Valderrama ◽  
Ana Belén Jódar-Reyes ◽  
Timothy J. Foster
Keyword(s):  
Aqueous Phase ◽  
Bile Salts ◽  
Oil In Water

scholarly journals Bile Salt Hydrolase of Bifidobacterium longum—Biochemical and Genetic Characterization

2000 ◽  
Vol 66 (6) ◽  
pp. 2502-2512 ◽  
Author(s):  
Hiroshi Tanaka ◽  
Honoo Hashiba ◽  
Jan Kok ◽  
Igor Mierau
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Bile Salt ◽  
Bile Salts ◽  
Bifidobacterium Longum ◽  
Bacillus Sphaericus ◽  
Site Directed Mutagenesis ◽  
Bile Salt Hydrolase ◽  
Ph Optimum ◽  
Human Bile

ABSTRACT A bile salt hydrolase (BSH) was isolated from Bifidobacterium longum SBT2928, purified, and characterized. Furthermore, we describe for the first time cloning and analysis of the gene encoding BSH (bsh) in a member of the genusBifidobacterium. The enzyme has a native molecular weight of 125,000 to 130,000 and a subunit molecular weight of 35,024, as determined from the deduced amino acid sequence, indicating that the enzyme is a tetramer. The pH optimum of B. longum BSH is between 5 and 7, and the temperature optimum is 40°C. The enzyme is strongly inhibited by thiol enzyme inhibitors, indicating that a Cys residue is likely to be involved in the catalytic reaction. The BSH ofB. longum can hydrolyze all six major human bile salts and at least two animal bile salts. A slight preference for glycine-conjugated bile acids was detected based on both the specificity and the Km values. The nucleotide sequence of bsh was determined and used for homology studies, transcript analysis, and construction and analysis of various mutants. The levels of homology with BSH of other bacteria and with penicillin V acylase (PVA) of Bacillus sphaericus were high. On the basis of the similarity of BSH and PVA, whose crystal structure has been elucidated, BSH can be classified as an N-terminal nucleophile hydrolase with Cys as the N-terminal amino acid. This classification was confirmed by the fact that a Cys1Ala exchange by site-directed mutagenesis resulted in an inactive protein. Reverse transcription-PCR experiments revealed that bsh is part of an operon containing at least two genes, bsh andglnE (GlnE is glutamine synthetase adenylyltransferase). Two UV-induced BSH-negative mutants and one spontaneous BSH-negative mutant were isolated from B. longum SBT2928 cultures and characterized. These mutants had point mutations that inactivatedbsh by premature termination, frameshift, or amino acid exchange.

scholarly journals In-cloud processes of methacrolein under simulated conditions – Part 2: Formation of secondary organic aerosol

2009 ◽  
Vol 9 (14) ◽  
pp. 5107-5117 ◽  
Author(s):  
I. El Haddad ◽  
L. Nieto-Gligorovski ◽  
V. Michaud ◽  
B. Temime-Roussel ◽  
E. Quivet ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Aqueous Phase ◽  
Mass Concentration ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Oh Radicals ◽  
Aerosol Formation ◽  
Esi Ms ◽  
Aerosol Mass Concentration

Abstract. The fate of methacrolein in cloud evapo-condensation cycles was experimentally investigated. To this end, aqueous-phase reactions of methacrolein with OH radicals were performed (as described in Liu et al., 2009), and the obtained solutions were then nebulized and dried into a mixing chamber. ESI-MS and ESI-MS/MS analyses of the aqueous phase composition denoted the formation of high molecular weight multifunctional products containing hydroxyl, carbonyl and carboxylic acid moieties. The time profiles of these products suggest that their formation can imply radical pathways. These high molecular weight organic products are certainly responsible for the formation of secondary organic aerosol (SOA) observed during the nebulization experiments. The size, number and mass concentration of these particles increased significantly with the reaction time: after 22 h of reaction, the aerosol mass concentration was about three orders of magnitude higher than the initial aerosol quantity. The evaluated SOA yield ranged from 2 to 12%. These yields were confirmed by another estimation method based on the hygroscopic and volatility properties of the obtained SOA measured and reported by Michaud et al. (2009). These results provide, for the first time to our knowledge, strong experimental evidence that cloud processes can act, through photooxidation reactions, as important contributors to secondary organic aerosol formation in the troposphere.

scholarly journals Demonstrating Aqueous-Phase Low-Molecular-Weight-Gel Wicking of Oil for the Remediation of Oil Spilled into Surface Water

Langmuir ◽  
2020 ◽  
Vol 36 (44) ◽  
pp. 13155-13165
Author(s):  
Daniel J. Walls ◽  
Emilie Espitalié ◽  
Gabriel Hum ◽  
Jun Chen ◽  
Michael Gattrell ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Surface Water ◽  
Aqueous Phase ◽  
Low Molecular Weight
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